Kmeans Algorithm

[Idx,C,sumD,D]=Kmeans(data,3,’dist’,’sqEuclidean’,’rep’,4)

等号右边:

Kmeans:K-均值聚类

data是你自己的输入数据

3 是你要聚成3类

dist sqEuclidean 这2个参数,表示距离函数为欧式距离。

’rep’,4 聚类重复次数4次。因为要反复算直到选出最好的结果,至多反复算4次

等号左边:

Idx 是你聚类的标号

C 是聚类之后质心的位置

sumD是所有点到质心的距离之和

D是每个点与所有质心的距离

比如下面这幅图中,输入数据data就是所有的小点,K-均值聚类输出的结果就是所有的数据被聚为了3类,聚类的标号就是红绿蓝三种颜色,每一类有一个自己的质心(大的点)。
在这里插入图片描述

具体见博客的网址:
https://www.cnblogs.com/hujj/archive/2012/04/11/2442351.html

import time import numpy as np import matplotlib.pyplot as plt from sklearn.cluster import MiniBatchKMeans, KMeans from sklearn.metrics.pairwise import pairwise_distances_argmin from sklearn.datasets import make_blobs # Generate sample data np.random.seed(0) batch_size = 45 centers = [[1, 1], [-1, -1], [1, -1]] n_clusters = len(centers) X, labels_true = make_blobs(n_samples=3000, centers=centers, cluster_std=0.7) # Compute clustering with Means k_means = KMeans(init='k-means++', n_clusters=3, n_init=10) t0 = time.time() k_means.fit(X) t_batch = time.time() - t0 # Compute clustering with MiniBatchKMeans mbk = MiniBatchKMeans(init='k-means++', n_clusters=3, batch_size=batch_size, n_init=10, max_no_improvement=10, verbose=0) t0 = time.time() mbk.fit(X) t_mini_batch = time.time() - t0 # Plot result fig = plt.figure(figsize=(8, 3)) fig.subplots_adjust(left=0.02, right=0.98, bottom=0.05, top=0.9) colors = ['#4EACC5', '#FF9C34', '#4E9A06'] # We want to have the same colors for the same cluster from the # MiniBatchKMeans and the KMeans algorithm. Let's pair the cluster centers per # closest one. k_means_cluster_centers = k_means.cluster_centers_ order = pairwise_distances_argmin(k_means.cluster_centers_, mbk.cluster_centers_) mbk_means_cluster_centers = mbk.cluster_centers_[order] k_means_labels = pairwise_distances_argmin(X, k_means_cluster_centers) mbk_means_labels = pairwise_distances_argmin(X, mbk_means_cluster_centers) # KMeans for k, col in zip(range(n_clusters), colors): my_members = k_means_labels == k cluster_center = k_means_cluster_centers[k] plt.plot(X[my_members, 0], X[my_members, 1], 'w', markerfacecolor=col, marker='.') plt.plot(cluster_center[0], cluster_center[1], 'o', markerfacecolor=col, markeredgecolor='k', markersize=6) plt.title('KMeans') plt.xticks(()) plt.yticks(()) plt.show() 这段代码每一句在干什么
06-01
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